Giacomo
by ThePillowS
Summary: Based on the comment: "What would happen if the Tenth Doctor and Captain Jack had a child?" There are crossovers of this sort, but none with this exact premise, so I thought I would give it a go. Crack, but slightly serious. Disclaimer: Do not own.


Author's Note: This is largely based on BBC's Casanova featuring David Tennant, so there are probably some historical discrepancies. Also I know in the film his hair is largely brown, but lets for the sake of this fic pretend they were more orange than they really were.

"So where are we this time?" Donna asked, steadying herself after the usual rough TARDIS trip. "I want to be prepared. Don't want a repeat of what happened on-"

"Oh it wasn't that bad." The Doctor switched the TARDIS controls off, parking her steadily.

"Wasn't that bad? I nearly froze to death the moment I stepped outside thanks to you forgetting to check the scanners! You think you'd mention you've taken me to the coldest cryogenic planet in the universe!"

The Doctor ran one hand through his hair, feeling just a bit guilty. "Alright then. It was supposed to be a surprise but, its Venice. Venice in the 1700s. Lovely city, full of aristocrats at the moment. I've heard the party scene is quite something."

Donna looked assuaged and pleased. "Well, I better get changed then. Has the TARDIS got Venetian 18th century fashion?" She started heading into the ship.

"Well yes, but what for?"

Donna looked back, incredulous. Men can be so thick. "What for? You expect me to waltz around 18th Century Europe in jeans and a jumper?"

"Oh they've got all sorts round here. Cosmopolitan city and all that. No one will even notice."

Donna scowled at the Doctor. "I'm not listening to you Mister 'conquer the world in a suit and converse'. For an alien you sure aren't afraid of stirring up unwanted attention. Besides," Donna smiled mischievously, "statesmen and aristocrats, maybe _I_ want to get noticed."

The Doctor rolled his eyes, folded his arms and leaned against the door of the TARDIS. What Donna wants, Donna gets.

A good while later, Donna finally stepped out into the control room, now in a slightly gaudy, lush purple dress with matching parasol. She did a dramatic twirl and jumped down the steps in Mary Poppins fashion.

The Doctor beamed at her, and held out his elbow. "Come on then, to the City of Water!"

"Doctor, Doctor." Donna tugged the Doctor's coat. She pointed at a figure a few paces from them, in the midst of the colorful crowd. "That man there, he looks like you." Donna looked at the Doctor, then back at the man. "He could be your twin!"

They've stumbled into a crowd of socializing well-to-dos around a fountain, all clad in a myriad of bright colors. The Doctor looked over to see a man in a rather alarming shade of aqua, bending to kiss a giggling woman's hand.

"Yes that's fascinating. Wrong eye color, and hair color. Oh he's ginger, and not rude at all. I like that."

"You're missing the point!" Donna emphasized every syllable, exasperated, "He looks compLETEly, eXACtly, LIKE you!"

The Doctor gave another look at the man. "Well its a big universe. Coincidences do happen. My alien tech scanner's not going off. There's no mystery here. He's a perfectly normal human being."

Donna was still craning a bit to look at the man. "Not like this. Maybe he's related to you or some'in."

The Doctor rolled his eyes impatiently. "Impossible. Just because humans look Timelord everybody suddenly forgets the intricacies of interspecies genetic exchange- Look, if you don't believe me, go talk to him. I'll bet he's got a mother and a father and was raised like a perfectly normal Earthling."

Donna did not need any more prompting. She lifted her slightly cumbersome dress and approached the man. Up close the resemblance did not lessen, but there were some differences. The man was much younger, probably in his early 20s, while the Doctor's current body was a good, well-aged 40 or so. The man also did not have the world-weary crease in the brows, or the century-worn hunch about the shoulders.

She came up to him, and, not sure what the manner was in 18th Century upper class, made a little ballerina courtesy. An amused smile graced the man's lips and he bowed back.

In her best aristocrat impression, with chin raised high, she declared, "I am Lady Donna of the Noble family. And who might you be?"

"Honored to meet you my fair lady. I'm Giacomo. Giacomo Casanova."

Donna's eyes widened and her mouth dropped until it formed a perfect, comical 'O'.

The man frowned at Donna's reaction. "Something the matter my lady?"

Donna shook her head slowly, eyes still wide as ever. "You've GOT to be kidding me."

The man looked confused. He had put on his best charming smile, this reaction was not expected.

"Casanova, THE Casanova? The most famous womanizer of all time?"

The man looked slightly taken aback, then smirked, reaching an alarming level of similarity between him and the Doctor. "The one and only. I don't know about the most famous, but I would not reject any title my lady bestows upon me."

He took Donna's hand and bent to kiss it, then laid another one on her wrist, eyes looking up at hers. Donna jerked her hand free. "Um, I left my friend back there. It was nice to meet you." And she fled.

"This is too uncanny." Donna treaded back to the Doctor, looking flushed and scandalized. "Do you know who that is? That's Casa-bloody-nova! Casanova! And he's got YOUR face!"

"Casanova?" the Doctor mused, "hm, for some reason, never wanted to meet him too badly. Not really my type."

"I can't believe the women all fell for this." Donna gestured to all of the Doctor. "Although, its probably that mouth of his. Definitely got a better personality than you."

"Did you check if he's got two hearts?" the Doctor asked absently.

"And how was I supposed to do that? Anyway I've got something better."

"What?" the Doctor looked down to see Donna's cheeky open-mouthed grin, holding up her hand with her thumb and forefinger pinched together. The Doctor bent down a bit, peered closer at her fingers. There was a brownish strand of hair in between.

"You can run it through your DNA checker or some'in, see if its alien!" Donna was more than pleased with herself.

The Doctor raised both eyebrows at Donna. "Impressive."

He reached his pockets, took the hair gingerly and stuck it in a small square-ish device. He put on his glasses.

"Yep, human." He began to put the device away, when a hunch struck him. He punched a few buttons.

"There's something weird. He's not a Time Lord, but he's got a bit of me, the shallowest bits, of this incarnation nonetheless and...something else, the DNA of someone else I've come into contact with, someone I know."

"So he's like Jenny? He's your son?"

The Doctor sighed. Jenny was not a pleasant memory. "Of sorts. Except he's only got one heart."

"He looks like me, but flirts with anything that walks. There's only one explanation. He's the offspring of me and Jack Harkness. The bastard even named him after himself."

"Who's Jack Harkness?" Donna asked, craning to look at the DNA identifier, as if expecting a picture of the man on there.

"Oh you'll meet him soon enough. You'll probably like him too. Come on, we're going back to the TARDIS." He started stalking at top speed, with Donna tottering after him, hitching her puffy skirt up with both hands. In typical Doctor fashion, he prattled on even as he walked.

"Of course, Jack was brought back by the power of the TARDIS, which was linked to me. When I regenerated, the vortex energy was blasting everywhere, and must have left an echo of me in him. A shallow echo, skin-deep, quite literally, even less than Jenny was."

"And so Casanova is..."

"His son, probably. Given that its Jack I'm not surprised."

"Jack, were you ever in the 18th century?"

Jack's winning smile faltered a little. "I lived through more than half of it, thanks to you Doctor."

"Right and during that time, did you ever have-" the Doctor gestured, "affairs?"

Jack gave him a look.

"Right, of course, you're Jack. Well, how many?"

Jack gave him another look.

"Right, of course, you're Jack." the Doctor ran a hand through his hair. "Well...do you remember all of them?"

Jack leered, "Do you fancy joining the ranks Doctor?"

The Doctor ignored him. "Did you leave any..souvenirs?"

Jack looked slightly offended. "I'm a 51st century man, I'm absolutely fool-proof at this."

"Not that I don't trust you Jack, but evidence suggests otherwise."

Jack blinked, and shifted just a little into a defensive stance, "What do you mean, evidence?"

"Not even once? In the heat of the moment, perhaps? Come on, Jack, think!"

The Doctor looked like he wanted to shake Jack by the shoulders, but kept well away, hands tucked beneath elbows. Jack could not help the twinge of hurt he felt. Despite everything, he still wanted to please the Doctor, it was his greatest power over others. So Jack thought back, thought hard. He'd had many lovers, oh yes, all over England and half the continent while he waited. But he was always careful. 51st century methods made sure these things left no consequences. Even at his most depraved, most lonely, even when he was broken and abandoned by one particular man, he had taken care to- wait, had he?

The Doctor could tell by Jack's deepening scowl that his suspicions had been confirmed.

"There was once, just after you left me behind." Jack swallowed, "I landed in 1724, somewhere in Venice. I watched a play, met the actress. Oh but she was charming."

The Doctor rolled his eyes, "Oh but I hardly think she was the one doing the charming."

"Well, ok, she was married, which I normally don't do, but that night-" Jack stopped, looking at the Doctor in the eye. "She was understanding, that's all."

"And you forgot, forgot all your 51st century methods?"

"Yeah so I did. I was confused. I didn't even know who I was anymore. I'd just became a changed man, a new man, thanks to you, and you left without even a good-bye." Hurt and anger was written all over Jack's face.

The Doctor looked down, not meeting the other man's eyes. An apology was half stumbling out of him but the words that came out were "I left you with more than just a good-bye."


End file.
